There is a specific set of sounds used in Japanese. Each is either a vowel sound, or a combination of a consonant and vowel, or the sound of the letter n.
The good news is any given sound is always said the sane way. No "I read the book, now you read the book" in Japanese. See the spelling in kana and you can pronounce it.
Of course, it isn't quite that easy. There are long and short vowels, double consonants, and silent characters. And within Japan, there are several dialects that sound different. The usage cited herein is generally that heard in Tokyo.
There are five vowels in the Japanese language. They are:
Where it says "rhymes with", you could add "always". Each of the sounds is said the same way every time. And each has the same length when speaking.
Vowels can be short or long. Consider the words oki and ookii. In the first case, the sound of o and i are short. If you spoke k with a metronome, it would take a count of two - o and ki.
But ookii would take a count of four (two for o, one for ki, one for the final i).
These are totally different words - oki means several different things - one is embers - while ookii means big. Yet the only difference is in their pronunciation - the length of the vowels.
Long vowels are said smoothly, that is, you don't say o o, you say o- as one sound but held longer. Think of oh and ooh, but with the same sound.
A long vowel is displayed in various ways. With hira gana, the vowel is written two times: いい (ii). the character o is usually written as おう (ou). With kata kana, a long vowel is followed by a dash: オー (oー). And with Romaji, it is usually written with a bar over each long vowel (o).
The vowels i and u are not always sounded. For instance, the common word desu and common verb ending masu are usually pronounced des' and mas' respectively. Similarly, the verb ending mashita is usually pronounced mash'ta. In each case, although no sound is made, the timing is as if the sound is made, and the mouth should be shaped as if it were making the sound.
The consonants are K G, S, J, Z, T, D, N, H, B, P, M, Y, R, and W. Note that Y is considered to be a consonant.
Notice also that there is no character for the sound of V, Q, L, or C (except as K). These sounds do not occur in Japanese speaking.
When using foreign words, r is usually used in place of l – thus erebeetaa (elevator)
A sound that is not in English is tsu. It sounds like the ts in cats.
Most consonants are pronounced the same as in English. Two exceptions are g and r. G is pronounced more like ng, as in ring. R is pronounced more like d – the tongue should touch the roof of the mouth when sounding r.
Consonants may also be stretched, but differently from vowels. With kana, a small tsu character indicates that the following consonant should be stretched: がっこう (gakkou) in hira gana, ガッコー in kata kana. With Romaji, printing the letter twice indicates that it is stretched: gakkou.
Some words are spelled with alternate characters for ease of speech. These are the sounds represented with the tenten (”) or maru (o) in kana. They are
Can be spelled with
Da/Ta (Rice field)
That is why there is hira gana and kata kana. Gana and kana mean the same thng.
This dissertation is only an introduction – there are many subtle points that a student of Japanese can study after mastering this much.